Root Cause Debugging
jsmastery-pro/skills
Runs a reproduce, localize, hypothesize, test, fix and verify loop to find a bug's root cause, applies the minimal fix and hands off a regression test.
Finds the root cause of a bug, test failure, or unexpected behavior before proposing any fix.
Install Systematic Debugging
$ npx skills add cbrock84/headcount --skill systematic-debugging -a claude-codeProject install by default; add -g for ~/.claude/skills/.
$ gh skill install cbrock84/headcount systematic-debugging --agent claude-codeProject scope by default; add --scope user for a personal install. Needs GitHub CLI 2.90.0 or later (public preview).
$ git clone --depth 1 https://github.com/cbrock84/headcount.git skills-src && mkdir -p .claude/skills && cp -r skills-src/plugins/technology/skills/systematic-debugging .claude/skills/systematic-debugging && rm -rf skills-srcUse ~/.claude/skills/ instead of .claude/skills for a personal install. The folder must contain SKILL.md.
Claude Code skills documentation · loads skills from .claude/skills/
Install the "systematic-debugging" agent skill from https://github.com/cbrock84/headcount/tree/main/plugins/technology/skills/systematic-debugging into .claude/skills/systematic-debugging/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "systematic-debugging", then confirm the skill loads.Claude Code copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$skill-installer install https://github.com/cbrock84/headcount/tree/main/plugins/technology/skills/systematic-debuggingType this inside Codex. $skill-installer <name> installs a curated skill from openai/skills. The installer writes to $CODEX_HOME/skills (default ~/.codex/skills). Restart Codex if the skill does not show up.
$ npx skills add cbrock84/headcount --skill systematic-debugging -a codexProject install goes to .agents/skills/; add -g for ~/.codex/skills/.
$ gh skill install cbrock84/headcount systematic-debugging --agent codexProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/cbrock84/headcount.git skills-src && mkdir -p .agents/skills && cp -r skills-src/plugins/technology/skills/systematic-debugging .agents/skills/systematic-debugging && rm -rf skills-srcUse ~/.agents/skills/ instead of .agents/skills for a personal install.
Codex skills documentation · loads skills from .agents/skills/
Install the "systematic-debugging" agent skill from https://github.com/cbrock84/headcount/tree/main/plugins/technology/skills/systematic-debugging into .agents/skills/systematic-debugging/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "systematic-debugging", then confirm the skill loads.Codex copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ npx skills add cbrock84/headcount --skill systematic-debugging -a cursorProject install goes to .agents/skills/; add -g for ~/.cursor/skills/.
$ gh skill install cbrock84/headcount systematic-debugging --agent cursorProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/cbrock84/headcount.git skills-src && mkdir -p .cursor/skills && cp -r skills-src/plugins/technology/skills/systematic-debugging .cursor/skills/systematic-debugging && rm -rf skills-srcUse ~/.cursor/skills/ instead of .cursor/skills for a personal install.
Cursor skills documentation · loads skills from .cursor/skills/, .agents/skills/, .claude/skills/, .codex/skills/
Install the "systematic-debugging" agent skill from https://github.com/cbrock84/headcount/tree/main/plugins/technology/skills/systematic-debugging into .cursor/skills/systematic-debugging/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "systematic-debugging", then confirm the skill loads.Cursor copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ gemini skills install https://github.com/cbrock84/headcount.git --path plugins/technology/skills/systematic-debugging--scope user (default) or --scope workspace; --path is the subfolder of the repo that holds the skill; --consent skips the security confirmation prompt.
$ npx skills add cbrock84/headcount --skill systematic-debugging -a gemini-cliProject install goes to .agents/skills/; add -g for ~/.gemini/skills/.
$ gh skill install cbrock84/headcount systematic-debugging --agent gemini-cliProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/cbrock84/headcount.git skills-src && mkdir -p .gemini/skills && cp -r skills-src/plugins/technology/skills/systematic-debugging .gemini/skills/systematic-debugging && rm -rf skills-srcUse ~/.gemini/skills/ instead of .gemini/skills for a personal install, then run /skills reload.
Gemini CLI skills documentation · loads skills from .gemini/skills/, .agents/skills/
Install the "systematic-debugging" agent skill from https://github.com/cbrock84/headcount/tree/main/plugins/technology/skills/systematic-debugging into .gemini/skills/systematic-debugging/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "systematic-debugging", then confirm the skill loads.Gemini CLI copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ gh skill install cbrock84/headcount systematic-debuggingInstalls for Copilot at project scope by default; add --scope user for a personal install. Preview a skill first with gh skill preview. Needs GitHub CLI 2.90.0 or later (public preview).
$ npx skills add cbrock84/headcount --skill systematic-debugging -a github-copilotProject install goes to .agents/skills/; add -g for ~/.copilot/skills/.
$ git clone --depth 1 https://github.com/cbrock84/headcount.git skills-src && mkdir -p .github/skills && cp -r skills-src/plugins/technology/skills/systematic-debugging .github/skills/systematic-debugging && rm -rf skills-srcUse ~/.copilot/skills/ instead of .github/skills for a personal install. Commit .github/skills so cloud agent and code review can use it.
GitHub Copilot skills documentation · loads skills from .github/skills/, .claude/skills/, .agents/skills/
Install the "systematic-debugging" agent skill from https://github.com/cbrock84/headcount/tree/main/plugins/technology/skills/systematic-debugging into .github/skills/systematic-debugging/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "systematic-debugging", then confirm the skill loads.GitHub Copilot copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ npx skills add cbrock84/headcount --skill systematic-debugging -a opencodeOpenCode documents no install command of its own. Project install goes to .agents/skills/; add -g for ~/.config/opencode/skills/.
$ gh skill install cbrock84/headcount systematic-debugging --agent opencodeProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/cbrock84/headcount.git skills-src && mkdir -p .opencode/skills && cp -r skills-src/plugins/technology/skills/systematic-debugging .opencode/skills/systematic-debugging && rm -rf skills-srcUse ~/.config/opencode/skills/ instead of .opencode/skills for a personal install.
OpenCode skills documentation · loads skills from .opencode/skills/, .claude/skills/, .agents/skills/
Install the "systematic-debugging" agent skill from https://github.com/cbrock84/headcount/tree/main/plugins/technology/skills/systematic-debugging into .opencode/skills/systematic-debugging/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "systematic-debugging", then confirm the skill loads.OpenCode copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
Facts
- Skill name
systematic-debugging- GitHub stars
- 2k
- Token cost
- ~657 tokens
- SKILL.md length
- 350 words
- Files
- 1
- Skills in repo
- 177
- Repo updated
- First seen
- Licence
- MIT
At a glance
Finds the root cause of a bug, test failure, or unexpected behavior before proposing any fix.
- Works in 6 steps: Reproduce it deterministically. If you… → Narrow the blast radius. Bisect: which… → State a hypothesis that can be wrong.… → …
- A fix has been attempted and did not work
- SKILL.md covers The rule, Method, Anti-patterns and Never, plus 1 more section
- Instructions only: no scripts, shell commands, URLs or credentials in SKILL.md
What it does
Systematic Debugging is an agent skill from cbrock84/headcount. Finds the root cause of a bug, test failure, or unexpected behavior before proposing any fix. Use this whenever something is broken and the cause is not yet proven — a failing test, a production error, intermittent behavior, or a symptom that appeared after a change. Also use when a fix has been attempted and did not work, or when the same bug keeps coming back.
Its SKILL.md is about 660 tokens, which your agent loads only when the skill is triggered. It is a single SKILL.md file with no bundled scripts.
It sits in Development, covering Failing and flaky tests, Debugging and Root cause analysis. The repository describes itself as: An agent organization structured as a company — 15+ departments, 125+ skills, each independently installable, citing the standards and regulators that settle the question. Runs… The licence is MIT.
When your agent uses it
- A fix has been attempted and did not work
- The same bug keeps coming back
Example prompts
- “Use the systematic-debugging skill to find the root cause of a bug, test failure, or unexpected behavior before proposing any fix”
- “/systematic-debugging”
Workflow steps
6 steps, taken from the first numbered list in SKILL.md.
- Reproduce it deterministically. If you cannot make it happen on demand, you cannot know when
- Narrow the blast radius. Bisect: which commit, which input, which branch, which layer. Halve
- State a hypothesis that can be wrong. "The cache returns stale rows after a write" is a
- Test the hypothesis directly — a log line, a breakpoint, a probe. Prove it, do not infer it.
- Explain the whole symptom. If your cause explains the error but not why it started Tuesday,
- Fix, then verify by reverting. Put the bug back and confirm the test fails again. This is the
What it can do on your machine
Read from SKILL.md and the folder at commit 98d1c17. It shows what the files ask for, not the result of running them.
Tool permissions
Pre-approves nothing: there is no allowed-tools line, so your agent's usual permission prompts apply.
From allowed-tools in the SKILL.md frontmatter.
Runs code
No scripts in the folder and no shell commands in SKILL.md.
From the folder's file list and the shell code blocks in SKILL.md.
Network
No URLs in SKILL.md.
From URLs in SKILL.md, links to its own repository left out.
Credentials
Names no API keys, tokens, secrets or passwords.
From names ending in _API_KEY, _TOKEN, _SECRET, _KEY or _PASSWORD in SKILL.md.
Context cost
Systematic Debugging loads about 657 tokens when it runs. Until then it costs about 96 tokens; SKILL.md has 350 words of instructions outside code blocks.
Estimates: characters ÷ 4, the usual rule of thumb; real counts depend on the model's tokenizer. Scripts and assets cost tokens only if the agent reads them.
Safety
Auto-check passed
The automated check found no risky patterns in SKILL.md.
Automated static check — not a guarantee. Review scripts before installing. It scans the text of SKILL.md for risky patterns (piping downloads into a shell, reading credential files, hidden Unicode, destructive commands); files beside SKILL.md are not scanned.
SKILL.md
The full file from cbrock84/headcount at commit 98d1c17, republished under its MIT licence (© cbrock84). 350 words, ~657 tokens.
Download SKILL.mdSave it as
.claude/skills/systematic-debugging/SKILL.md (or your agent's skills folder).- name
- systematic-debugging
- description
- Finds the root cause of a bug, test failure, or unexpected behavior before proposing any fix. Use this whenever something is broken and the cause is not yet proven — a failing test, a production error, intermittent behavior, or a symptom that appeared after a change. Also use when a fix has been attempted and did not work, or when the same bug keeps coming back.
Systematic debugging
The rule
No fix before the cause is proven. A change that makes a symptom disappear without an explanation has not fixed anything — it has moved the failure somewhere you are not looking.
Method
- Reproduce it deterministically. If you cannot make it happen on demand, you cannot know when it is fixed. Intermittent means you have not found the variable yet — order, timing, state, environment, data.
- Narrow the blast radius. Bisect: which commit, which input, which branch, which layer. Halve the search space with each step rather than reading everything.
- State a hypothesis that can be wrong. "The cache returns stale rows after a write" is a hypothesis. "Something is wrong with caching" is not.
- Test the hypothesis directly — a log line, a breakpoint, a probe. Prove it, do not infer it.
- Explain the whole symptom. If your cause explains the error but not why it started Tuesday, you have found a bug, not the bug.
- Fix, then verify by reverting. Put the bug back and confirm the test fails again. This is the step people skip, and it is the one that proves causation rather than coincidence.
Show full SKILL.md (154 more words)Show less
Anti-patterns
- Shotgun changes — altering several things at once. Now you cannot attribute the fix.
- "Probably a flake." Not a diagnosis. A test that fails intermittently is reporting a real race, ordering dependency, or shared-state leak.
- Fixing the symptom — catching the exception, adding a retry, widening a timeout — without knowing what threw it.
- Trusting the error message's location. Where it surfaced is rarely where it originated.
Never
- Close a bug without a reproduction that failed before the fix and passes after it.
- Deploy a change to production to find out whether it works. Reproduce somewhere you can observe first.
- Change the environment and the code in the same step.
- Leave a debugging aid in the code as the fix — a widened timeout, a disabled check, a swallowed exception.
Return contract
State the reproduction, the proven cause, the fix, and the verification that the fix addresses that cause specifically. Name anything you ruled out and how.
© cbrock84, MIT. Rendered from Markdown: HTML in the file is shown as text, images as links, and headings moved down two levels. Raw file
Files
Just SKILL.md in plugins/technology/skills/systematic-debugging of cbrock84/headcount.
Open the folder on GitHubat commit 98d1c17
Compare with similar skills
Systematic Debugging next to the 5 skills that share the most tags, products or categories with it. Stars are the repository's; “used in” counts other GitHub owners with a copy.
| Skill | Stars | Used in | Tokens | Auto-check | Licence | Repo updated |
|---|---|---|---|---|---|---|
| Systematic Debugging this skillcbrock84/headcount | 2k | — | ~657 | Automated safety check: Pass | MIT | |
| Root Cause Debuggingjsmastery-pro/skills | 1.4k | — | ~1.8k | Automated safety check: Notes | MIT | |
| Superpowers Systematic Debuggingchristopherarter/superpowers-reasonix | 102 | — | ~2k | Automated safety check: Pass | MIT | |
| Minimal Code Fixcobusgreyling/loop-engineering | 11k | 1 repos | ~345 | Automated safety check: Notes | MIT | |
| Failure Diagnosis LoopTotoro-jam/battle-tested-patterns | 343 | — | ~319 | Automated safety check: Pass | MIT | |
| Hypothesis-Driven DebuggingLichAmnesia/lich-skills | 234 | — | ~2.5k | Automated safety check: Pass | MIT |
Similar skills
Superpowers Systematic Debugging
christopherarter/superpowers-reasonix
Any bug, failing or flaky test, or surprise behavior?. An agent skill from christopherarter/superpowers-reasonix.
Minimal Code Fix
cobusgreyling/loop-engineering
Makes the smallest code change that fixes one well-scoped problem, such as a CI failure, review comment or typo, without refactoring anything unrelated.
Failure Diagnosis Loop
Totoro-jam/battle-tested-patterns
Walks the agent through a fixed loop for failing tests and build errors: reproduce, isolate, hypothesize, instrument, fix, verify, then add a regression test.
Hypothesis-Driven Debugging
LichAmnesia/lich-skills
Replaces trial-and-error fixing with an observe, hypothesize, experiment and conclude loop kept in DEBUG.md, where no fix is allowed before evidence supports a cause.
Test Guided Bug Detector
ArabelaTso/Skills-4-SE
Analyze failing tests to detect functional bugs in code. An agent skill from ArabelaTso/Skills-4-SE.
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Related
Categories
Questions about Systematic Debugging
What does Systematic Debugging do?
Finds the root cause of a bug, test failure, or unexpected behavior before proposing any fix. Systematic Debugging is an agent skill from cbrock84/headcount. Finds the root cause of a bug, test failure, or unexpected behavior before proposing any fix.
When should I use Systematic Debugging?
Systematic Debugging fits situations like: A fix has been attempted and did not work; the same bug keeps coming back.
How do I install Systematic Debugging in Claude Code?
Run `npx skills add cbrock84/headcount --skill systematic-debugging -a claude-code`. Or copy the skill folder (plugins/technology/skills/systematic-debugging in cbrock84/headcount) into .claude/skills/systematic-debugging in your project. Claude Code loads it when a task matches its description.
How do I install Systematic Debugging in Codex?
Run `npx skills add cbrock84/headcount --skill systematic-debugging -a codex`. Or copy the skill folder (plugins/technology/skills/systematic-debugging in cbrock84/headcount) into .agents/skills/systematic-debugging in your project. Codex loads it when a task matches its description.
Can I use Systematic Debugging in Cursor, Gemini CLI or GitHub Copilot?
Cursor, Gemini CLI, GitHub Copilot and OpenCode also load SKILL.md folders. With the skills CLI, run `npx skills add cbrock84/headcount --skill systematic-debugging -a cursor` (or -a gemini-cli, github-copilot or opencode for the others). To copy it by hand, put the folder in .cursor/skills/systematic-debugging, .gemini/skills/systematic-debugging, .github/skills/systematic-debugging and .opencode/skills/systematic-debugging in your project.
What does Systematic Debugging need to run?
SKILL.md names no scripts, command-line tools or credentials: Systematic Debugging is instructions for the agent only.
Does Systematic Debugging access the network?
SKILL.md contains no URLs. Any network use would come from the scripts or tools the agent runs. This is read from the text; nothing was executed.
Is Systematic Debugging safe to install?
Our automated static check of SKILL.md found no risky patterns, such as piping downloads into a shell, reading credential files or hidden Unicode. It is not a guarantee. Review the folder before installing.
What licence does Systematic Debugging use?
Systematic Debugging is published under the MIT licence (the repository's licence). It allows redistribution, so the full SKILL.md is shown on this page.
How many tokens does Systematic Debugging use?
About 657 tokens (SKILL.md is roughly 2.6k characters). Agents keep only the skill's name and description in context until a task matches; then they load SKILL.md in full.
What are the alternatives to Systematic Debugging?
Skills that share tags, products or a category with Systematic Debugging: Root Cause Debugging (jsmastery-pro/skills, 1.4k stars), Superpowers Systematic Debugging (christopherarter/superpowers-reasonix, 102 stars), Minimal Code Fix (cobusgreyling/loop-engineering, 11k stars) and Failure Diagnosis Loop (Totoro-jam/battle-tested-patterns, 343 stars). The comparison table on this page puts their stars, adoption, token cost, safety result and licence side by side.
Who maintains Systematic Debugging?
cbrock84 (a GitHub user) maintains it in cbrock84/headcount, which has 2,001 GitHub stars. The repository holds 177 skills in this directory. The repository was last updated on September 17, 2026.
Source: cbrock84/headcount on GitHub. Facts on this page come from the repository at the commit we read; the author's words are quoted as theirs.